/*
 * Copyright 2002-2012 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.beans.propertyeditors;

import java.beans.PropertyEditorSupport;
import java.io.IOException;

import org.springframework.core.io.Resource;
import org.springframework.core.io.ResourceEditor;
import org.springframework.util.Assert;

/**
 * One-way PropertyEditor which can convert from a text String to a
 * {@code java.io.InputStream}, interpreting the given String
 * as Spring resource location (e.g. a URL String).
 *
 * <p>Supports Spring-style URL notation: any fully qualified standard URL
 * ("file:", "http:", etc) and Spring's special "classpath:" pseudo-URL.
 *
 * <p>Note that in the default usage, the stream is not closed by Spring itself!
 *
 * 输入流编辑器
 *
 * @author Juergen Hoeller
 * @since 1.0.1
 * @see java.io.InputStream
 * @see org.springframework.core.io.ResourceEditor
 * @see org.springframework.core.io.ResourceLoader
 * @see URLEditor
 * @see FileEditor
 */
public class InputStreamEditor extends PropertyEditorSupport {

    /**
     * 资源编辑器
     */
    private final ResourceEditor resourceEditor;


    /**
     * Create a new InputStreamEditor,
     * using the default ResourceEditor underneath.
     *
     * 构造方法
     */
    public InputStreamEditor() {
        this.resourceEditor = new ResourceEditor();
    }

    /**
     * Create a new InputStreamEditor,
     * using the given ResourceEditor underneath.
     *
     * 构造方法
     *
     * @param resourceEditor the ResourceEditor to use
     */
    public InputStreamEditor(ResourceEditor resourceEditor) {
        Assert.notNull(resourceEditor, "ResourceEditor must not be null");
        this.resourceEditor = resourceEditor;
    }


    /**
     * 设置
     *
     * @param text
     * @throws IllegalArgumentException
     */
    @Override
    public void setAsText(String text) throws IllegalArgumentException {
        this.resourceEditor.setAsText(text);
        Resource resource = (Resource) this.resourceEditor.getValue();
        try {
            setValue(resource != null ? resource.getInputStream() : null);
        } catch (IOException ex) {
            throw new IllegalArgumentException(
                    "Could not retrieve InputStream for " + resource + ": " + ex.getMessage());
        }
    }

    /**
     * This implementation returns {@code null} to indicate that
     * there is no appropriate text representation.
     *
     * 获取
     */
    @Override
    public String getAsText() {
        return null;
    }

}
